From 2b39ce9bc8ceef8e6ea22ae635f963ce1943848f Mon Sep 17 00:00:00 2001
From: Petr Pucil <petr.pucil@seznam.cz>
Date: Mon, 27 Apr 2020 23:25:47 +0200
Subject: [PATCH] Simplify ReadBitsIntBe as in
 kaitai-io/kaitai_struct_java_runtime@e1a30e4

---
 KaitaiStream.cs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/KaitaiStream.cs b/KaitaiStream.cs
index 5a1bf06..936dd81 100644
--- a/KaitaiStream.cs
+++ b/KaitaiStream.cs
@@ -307,11 +307,9 @@ namespace Kaitai
 
             // raw mask with required number of 1s, starting from lowest bit
             ulong mask = GetMaskOnes(n);
-            // shift mask to align with highest bits available in "bits"
+            // shift "bits" to align the highest bits with the mask & derive reading result
             int shiftBits = BitsLeft - n;
-            mask = mask << shiftBits;
-            // derive reading result
-            ulong res = (Bits & mask) >> shiftBits;
+            ulong res = (Bits >> shiftBits) & mask;
             // clear top bits that we've just read => AND with 1s
             BitsLeft -= n;
             mask = GetMaskOnes(BitsLeft);